Agricultural planters are commonly used implements to plant seeds in soil. An agricultural planter can include a chassis that carries one or more storage tanks carrying seed, and chemical applications that are to be applied to the field during the planting operation, a hitch mechanism that attaches to a tractor or other implement pulled by a tractor, and a tool bar that row units can be connected to so they are carried by the chassis. The planter can also include a pneumatic system carried by the chassis that supplies pressurized air to transport the seeds or other particulate from the storage tanks to the row units.
Each row unit of the agricultural planter places seeds in the field. Typically, the row units are laterally arranged along a length of the tool bar so that as the planter is pulled across the field, each row unit plants seeds at predefined intervals along the path it is pulled across. To plant seeds, the row units perform four main operations as they are pulled: opening a trench in the soil; placing a seed into the formed trench at appropriate intervals; closing the formed trench to put soil on top of the placed seed; and packing soil on top of the seed to provide desirable soil contact with the placed seed. To open a trench in the soil, a furrowing disc system, which may include an opening disc, cuts into the soil and rotates, dislocating soil as it rotates to form the trench. Once the trench is open, a seed is placed in the trench by a metering device which receives seeds from the main storage tank(s) or a row unit storage tank and typically utilizes a combination of differential air pressure, to select the seed, and gravity to place the seed in the trench at predefined intervals along the pulled path so that adjacent seeds in the row are not too close to one another. One or more closing discs carried behind the furrowing disc are pressed into the soil and also rotate as the planter is pulled to replace soil dislocated by the furrowing disc in the trench or dislocate adjacent soil into the trench to cover the seed placed in the trench with soil. Finally, a pressing wheel carried behind the closing disc(s) exerts pressure on the soil covering the seed to press the soil down onto the seed and provide good soil contact with the seed. By having multiple row units working in unison as the planter is pulled across a field, many seeds can be effectively planted in an efficient manner.
One issue that can arise during planting is due to the row units all being connected to the tool bar, which may trail the tractor or other vehicle pulling the planter by a significant distance. When the vehicle pulling the planter traverses uneven terrain, such as a hill in the field, the wheels of the vehicle pulling the planter may be at a different elevation than wheels of the row units which are being pulled along with the tool bar. This difference in elevations can lead to the center frame of the planter being angled with respect to the ground plane on which the row units are traveling, which can cause the row units to either dig into the ground or be pulled away from the ground as the planter is being towed. When the row units are either digging into or being pulled away from the ground, this detrimentally impacts the row units' ability to provide uniform seed depth and spacing, compact seed trenches effectively, and close the formed trenches; further, the pressing wheels may also experience accelerated wear.
What is needed in the art is an agricultural implement which can overcome some of the previously described issues associated with known agricultural implements.